The present invention is related to perimeter security and search and rescue systems, in general, and more particularly, to a system for and method of laser scanning a perimeter zone around a target site to render an awareness of potential threats to such target site, and a system for and method of laser scanning a perimeter zone of water around a search vehicle to detect an object floating in the water.
With the increase of worldwide asymmetric terrorist activities, close in and long range proximity identification of potential threats to a target is of paramount interest. Today such threats may come in many forms such as suicide bombers, car bombs, shoulder launched missiles, rocket propelled grenades, and saboteurs among others. Terrorist targets such as heavily populated civilian and governmental facilities, military bases, aircraft, marine vessels and commercial businesses, for example, continue to expand worldwide. Likewise, these threats have also escalated in severity to now include real scenarios of chemical, biological, and nuclear attacks. As such, the role of intelligence, surveillance, reconnaissance, and countermeasure action has and will continue to be critical in preventing attacks on such targets.
In response to these emerging threats, it is of the ut-most importance to proactively monitor the surrounding land and waterside perimeter of threat vulnerable targets. Specifically, potential target sites such as ports and harbors, vast areas of land at airports and nuclear sites, military installations, high visibility sporting events, marine vessels, aircraft and others have come to the forefront requiring the detection of object motion and presence. Early identification and warning of objects within a perimeter of a target is critical in assessing potential threats and taking appropriate counter-terrorism/military measures. As a result of our historically open society, terrorists have numerous opportunities to strike our society at vulnerable targets which heretofore may have only been passively monitored with a security camera, if at all.
Current perimeter security systems and processes have been demonstrated to be insufficient for these emerging threats. For example, video cameras, night vision systems, radar, and conventional security patrols have proven ineffective at preventing recent terrorist attacks. Recent events such as the bombing of the USS Cole, a French oil tanker in Yemen, airport security breaches, car and suicide bombings, and the launching of rocket propelled grenades might have been avoided with an early warning system capable of detecting and tracking motion of objects on the ground or water. In each case, assailants penetrated traditional security layers of manned surveillance, video camera, or no security at all to launch an attack. Early identification and geolocation of potential ground and marine threats may be critical in thwarting attempts and securing and sustaining economic, commercial and military operations worldwide.
In addition, use of conventional radar systems for threat monitoring may result in confusion due to multi-path returns over water and will suffer from radar “clutter” at close in ranges (blind radar zones). These blind zones, depending upon the radar power, may be on the order of hundreds of meters to kilometers, for example. Additionally, changes in sea states can degrade the detection performance of the radar system even further. Algorithms have been developed in an attempt to suppress the noise generated due to multiple scattering paths from interaction with swells and short period surface wave action, but generally are targeted for detection of large objects, such as ships, for example, over many kilometers. Further, radar systems also suffer from broad main beam lobes, on the order of 1-10 degrees. To generate this level of directivity, side lobes can also be generated creating multi-path propagation, further reducing the fine detail detection of conventional radar systems.
Also, as in the case of a search and rescue of a survivor at sea, like a downed pilot, for example, a person's body floating in water may be detected by a conventional passive infrared system relying on the thermal difference between the body and the water. As the body temperature can be different than that of the water, the body of a terrorist may be detected by passive infrared sensors. However, the body temperature of a terrorist may be disguised. Once the body temperature of the terrorist approaches that of the surrounding water, the ability to detect the body with passive infrared sensors quickly diminishes, i.e. the thermal gradients necessary for an infrared body signature are lost. Thus, under these circumstances, conventional passive infrared imaging systems may miss detecting the terrorist's body in the water.
Likewise, in searching for persons in the water as in the case of a search and rescue mission, while living, sufficient thermal gradients may exist to enable thermal detection of the person. However, once deceased, the body temperature approaches that of the water. In this case, use of thermal imaging for recovery is voided.
The present invention overcomes the aforementioned drawbacks of the current perimeter security and search and rescue systems and provides a laser perimeter awareness system (LPAS) which utilizes a laser obstacle awareness system for monitoring a perimeter around a vulnerable target for rendering an awareness of potential threats to such target or for monitoring a perimeter of water around a search vehicle for detecting an object floating in the water.